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This article introduces the knowledge of "how to access and change physical data in ADO.NET". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

Before giving you a detailed introduction to ADO.NET entity data, let us first understand the entity framework structure, and then a comprehensive introduction to ADO.NET entity data. The entity framework is not only another object-relational mapping solution, but also fundamentally enables applications to access and change ADO.NET entity data and relational data represented as conceptual models. Object services use EDM to convert object queries against the ADO.NET entity data types represented in the conceptual model into data source-specific queries.

The query result is specified as the object managed by the object service. The entity framework provides the following ways to query EDM and return objects:

◆ LINQ to Entities-provides language integrated query (LINQ) support for querying entity types defined in the conceptual model. For more information, see Overview of LINQ to Entities.

◆ Entity SQL-a storage-independent SQL dialect that uses entities in the conceptual model directly and supports EDM features such as inheritance and relationships. Entity SQL can be used for object queries and queries executed using the EntityClient provider. For more information, see Overview of Entity SQL.

◆ query Builder method-- enables you to construct Entity SQL queries using LINQ-style query methods. For more information, see query Builder methods (entity Framework).

EntityClient data providers are included in the entity framework. This provider manages connections, converts entity queries into data source-specific queries, and returns a data reader used by object services to materialize entity data into objects. The EntityClient provider can also be used like a standard ADO.NET data provider by having the application execute an Entity SQL query and use the returned read-only data reader when the object materialization is not required. For more information, see for entity Framework EntityClient providers. The following figure shows the entity framework architecture for accessing data:

Entity frame structure diagram

The entity framework generates a class derived from ObjectContext that represents the entity container in the conceptual model. This object context provides the ability to track changes and manage identities, concurrency, and relationships. This class also exposes SaveChanges methods that write insert, update, and delete operations to the data source. Similar to queries, these changes are performed by commands automatically generated by the system or by stored procedures specified by the developer. For more information, see adding, modifying, and deleting objects (entity Framework).

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